1. Field of the Invention
The present invention relates in general to bone marrow biopsy devices and, more particularly, to a bone marrow biopsy device with a grip enhancement feature and a securable locking mechanism.
2. Background Art
Bone marrow biopsy devices have been known in the art for many years. In particular, many bone marrow biopsy devices have included a hollow outer cannula with some form of inner rod slidable within the outer cannula. The outer cannula conventionally consists of a proximal end, a distal end and some form of a handle associated with the proximal end. The inner rod may typically take several different forms, including a sharpened stylet for insertion of the bone marrow biopsy needle into a patient, an inner cannula for sampling bone marrow, and/or an ejector rod for forcing the sample out of the outer cannula. The inner rod also typically includes a second or connection handle which may be secured to the handle portion of the outer cannula.
For instance, Baldridge, U.S. Pat. No. 5,357,974, Tretinyak, U.S. Pat. No. 4,403,617, Tretinyak, U.S. Pat. No. 4,630,616, Lee, U.S. Pat. No. 4,655,266 and Strasser et al., U.S. Pat. No. 4,838,282 all disclose bone marrow biopsy devices having a first handle mounted on the outer cannula and a second handle mounted on the inner rod. The first and second handle portions of these devices are constructed from the same material, typically a light weight plastic. Moreover, these handles are usually designed to securably mate with one another, for instance by a locking member, such as that taught in Mittermeier et al., U.S. Pat. No. 6,063,037, incorporated herein by reference.
Additionally, several of these bone marrow biopsy devices have included handle features which enhance the ability of a user to both grip and manipulate the bone marrow biopsy needle. For instance, Strasser, U.S. Pat. No. 4,838,282 discloses finger grooves in the outer cannula handle portion, while Tretinyak, U.S. Pat. No. 4,403,617 discloses ridges on both the first and second handle portions to facilitate a user's grasping of the device.
Although these and other bone marrow biopsy devices have worked well, it is still desired to provide an enhanced gripping surface which enhances the feel for a user of the instrument, while at the same time preventing slipping of a hand or fingers which grasp the handle portion of the instrument. It is likewise desired to provide an enhanced gripping surface which works well in condition where water, perspiration or other fluid may be present.
It is further desired to provide a bone marrow biopsy device with a handle having a cushioned gripping portion. In particular, many bone marrow biopsy devices must inherently be forced by a physician for insertion into a patient's bone, thus mandating a firm, tight grip on the handle of the instrument. It is beneficial to provide a softer, cushioned surface to alleviate some of the stress placed on the physician's hand.
It is also desirable to provide a bone marrow biopsy device with a handle which is easily molded, and which includes inserts which add to the weight of the handle and improve weight distribution throughout the handle. It is likewise desirable to provide an inexpensive, easily positioned insert which contributes to a comfortable handle weight, while also enhancing the grip of the handle.
It is also desired to provide a bone marrow biopsy device with a gripping surface which enhances the secured, locking relationship of the outer cannula handle portion to the inner rod handle portion, to facilitate simultaneous use of the outer cannula in conjunction with the inner rod, for insertion, manipulation, and removal of the bone marrow biopsy device from a patient.
With regard to yet other device features, numerous bone marrow biopsy devices in the prior art have provided a secure, locked engagement between the cannula and rod handle segments. Many of these have required rotation of one of the handles themselves to return them to an unlocked orientation, resulting in a change in the orientation of the handles with respect to one another. This change in orientation of the handles, however, also causes a corresponding change in the orientation of the inner rod with respect to the outer cannula, which can be undesirable to the user. Likewise, the manipulations of the overall device while in use can inadvertently separate the cannula handle from the rod handle, unlocking the device and causing the aligned tips of the cannula and rod to become misaligned. For many applications, the user will want to remove the inner rod while the bone marrow biopsy device is inserted into a patient, and undesired rotation of the inner rod during removal may jeopardize the patient or the sample which the user wishes to remove. These bone marrow biopsy devices also present an increased risk of accidental separation of the handles during insertion of the device into the patient, due to unintended rotation of the handles with respect to one another caused by the twisting force exerted on the handle by the user as he attempts to force the device through the patient's bone and tissue.
In yet other lockable biopsy devices, a locknut securing device positioned directly atop the inner rod must be repeatedly rotated for removal, thereby allowing the user to directly remove the rod itself from the interior of the cannula. These devices typically do not include a handle at all for the rod and are often difficult to use, particularly with regard to the handling of the rod after it has been removed from the cannula.
As a result, it is desired to provide a bone marrow biopsy device with separate handle segments for both the cannula and rod elements, having an independent locking element which provides a secure, locked engagement between the two handles and yet allows the user to lock and unlock the handles without having to affect the orientation of the handles with respect to one another. It is further desired to allow the user of the bone marrow biopsy device to readily unlock and separate the handles, in order to remove the inner rod, without affecting their orientation, in order to prevent an undesired corresponding change in orientation of the inner rod distal end with respect to the outer cannula distal end.
It is also desired to provide a bone marrow biopsy device with a gripping surface which lessens the risk of accidental unlocking and separation of the handles--by preventing the palm of the user's hand from coming into inadvertent contact with the locking element.
These and other objects of the present invention will become apparent in light of the present specification, claims and drawings.